Lynch screening and genetic testing in endometrial cancer in a diverse population.
Authors: Kee-Hwan Michael Kim, Judy Hayek, Cheyenne Acker, Anjile An, Peilin Zhang, Constantine Gorelick, Margaux Jenna Kanis
Journal: Journal of Clinical Oncology (2023)

e17619 Background: Lynch syndrome (LS) accounts for most of the inherited endometrial cancers. Universal screening of endometrial tumors for defects in DNA mismatch repair (MMR) is recommended using immunohistochemistry (IHC) to identify which patients qualify for genetic counseling and testing. We report Lynch screening and genetic testing rates at a New York City tertiary care center with a large minority population, while investigating any potential disparities. Methods: This is a retrospective cohort study of patients with newly diagnosed endometrial cancer between January 2014 and June 2022. Data were obtained from pathology and chemotherapy databases at the NewYork-Presbyterian Brooklyn Methodist Hospital. Variables including age, race, ethnicity, BMI, insurance, language, family history of cancer, date of diagnosis, stage, MMR IHC, and genetic counseling/testing status were manually extracted. Descriptive statistics were used. Chi-square/Fisher’s exact tests were used to examine the association between genetic counseling/testing and categorical variables. Wilcoxon rank-sum/t-tests were used for continuous factors. The Mann-Kendall trend test was used to determine the significance of time trends. Results: 373 patients were identified. 45% identified as white, 42% black, 1.3% Asian, 12% other/unknown; 8.3% were of Hispanic ethnicity and 18% were non-English speaking. Mean age at diagnosis was 66 years (SD:10). 207 (55%) patients were screened using MMR IHC. 82 (40%) of these patients had MMR deficiencies on IHC. Of these, 63 (77%) received genetic counseling. 62 (98%) of those counseled subsequently underwent genetic testing, and ultimately 7 (11%) were diagnosed with LS. The overall rate of LS detected was 1.9% in the study population. The rate of MMR IHC testing has been increasing, reaching 95% in 2021 and 100% in 2022. It was associated with significant differences in mean age at diagnosis (p &lt; 0.01) and insurance type (p = 0.04). 45% of patients that received MMR IHC had private insurance, compared to 34% of patients that did not. The rate was not influenced by race, language, BMI, family history of cancer, or stage. The proportion of patients that received genetic counseling and testing for endometrial cancer also showed a significant upwards trend over time (p &lt; 0.01). Genetic counseling and testing rates were significantly different by ethnicity (p = 0.03), with only 3.0% of patients receiving genetic counseling/testing identifying as Hispanic. 98% of genetic counseling was performed by a gynecologic oncologist, as opposed to a genetic counselor. Conclusions: There were no disparities in access to initial IHC screening in this diverse patient population, however more work must be done to reach all ethnicities for genetic counseling and testing. The rate of LS detected was less than the known prevalence in endometrial cancer, possibly indicating demographic differences or gaps in screening.